// Problem: 
// Contest: 
// URL: 
// Memory Limit: 
// Time Limit: 
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#include<bits/stdc++.h>
using namespace std;
#define int long long
inline int read(){
	int s=0,w=1;
	char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}
	while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();
	return s*w;
}
signed main()
{
	int t=1;
//	cin>>t;
	while(t--)
	{
		int n;
		cin>>n;
		for(int i=1;i<=n;i++)
		{
			int h1,m1,s1,h2,m2,s2,d=0;
			scanf("%lld:%lld:%lld %lld:%lld:%lld",&h1,&m1,&s1,&h2,&m2,&s2);
			if(getchar()==' ')scanf("(+%lld)",&d);
			int a=(d*86400+h2*3600+m2*60+s2)-(h1*3600+m1*60+s1);
			d=0;
			scanf("%lld:%lld:%lld %lld:%lld:%lld",&h1,&m1,&s1,&h2,&m2,&s2);
			if(getchar()==' ')scanf("(+%lld)",&d);
			int b=(d*86400+h2*3600+m2*60+s2)-(h1*3600+m1*60+s1);
			int ans=b+a>>1;
			printf("%02lld:%02lld:%02lld\n",ans/3600,ans%3600/60,ans%60);
		}
	}
	return 0;
}
